US11201498B2 - Power supply system - Google Patents

Power supply system Download PDF

Info

Publication number
US11201498B2
US11201498B2 US16/828,892 US202016828892A US11201498B2 US 11201498 B2 US11201498 B2 US 11201498B2 US 202016828892 A US202016828892 A US 202016828892A US 11201498 B2 US11201498 B2 US 11201498B2
Authority
US
United States
Prior art keywords
power source
switch
state
power
load
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
US16/828,892
Other versions
US20200343763A1 (en
Inventor
Kazuhisa WATARU
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Yazaki Corp
Original Assignee
Yazaki Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Yazaki Corp filed Critical Yazaki Corp
Assigned to YAZAKI CORPORATION reassignment YAZAKI CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: WATARU, KAZUHISA
Publication of US20200343763A1 publication Critical patent/US20200343763A1/en
Application granted granted Critical
Publication of US11201498B2 publication Critical patent/US11201498B2/en
Assigned to YAZAKI CORPORATION reassignment YAZAKI CORPORATION CHANGE OF ADDRESS Assignors: YAZAKI CORPORATION
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J9/00—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
    • H02J9/04—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source
    • H02J9/06—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J9/00—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
    • H02J9/04—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source
    • H02J9/06—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems
    • H02J9/068—Electronic means for switching from one power supply to another power supply, e.g. to avoid parallel connection
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
    • B60R16/00—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for
    • B60R16/02—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for electric constitutive elements
    • B60R16/03—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for electric constitutive elements for supply of electrical power to vehicle subsystems or for
    • B60R16/033—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for electric constitutive elements for supply of electrical power to vehicle subsystems or for characterised by the use of electrical cells or batteries
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L1/00—Supplying electric power to auxiliary equipment of vehicles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L3/00—Electric devices on electrically-propelled vehicles for safety purposes; Monitoring operating variables, e.g. speed, deceleration or energy consumption
    • B60L3/0023—Detecting, eliminating, remedying or compensating for drive train abnormalities, e.g. failures within the drive train
    • B60L3/0046—Detecting, eliminating, remedying or compensating for drive train abnormalities, e.g. failures within the drive train relating to electric energy storage systems, e.g. batteries or capacitors
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L3/00—Electric devices on electrically-propelled vehicles for safety purposes; Monitoring operating variables, e.g. speed, deceleration or energy consumption
    • B60L3/0092—Electric devices on electrically-propelled vehicles for safety purposes; Monitoring operating variables, e.g. speed, deceleration or energy consumption with use of redundant elements for safety purposes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
    • B60L58/10—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries
    • B60L58/18—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries of two or more battery modules
    • B60L58/20—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries of two or more battery modules having different nominal voltages
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
    • B60R16/00—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for
    • B60R16/02—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for electric constitutive elements
    • B60R16/03—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for electric constitutive elements for supply of electrical power to vehicle subsystems or for
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J1/00—Circuit arrangements for DC mains or DC distribution networks
    • H02J1/10—Parallel operation of DC sources
    • H02J1/108—Parallel operation of DC sources using diodes blocking reverse current flow
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/36—Arrangements using end-cell switching
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J9/00—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
    • H02J9/04—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source
    • H02J9/06—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems
    • H02J9/061—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems for DC powered loads

Definitions

  • the present invention relates to a power supply system that is available, for example, to provide power to an important load in an in-vehicle system.
  • a vehicle such as an automobile has various functions for realizing stable traveling. Further, for example, more advanced functions such as driving operation assistance of a driver or automation of driving may be installed, and more and more advanced functions tend to be added in the future.
  • the in-vehicle system for realizing such advanced functions includes, for example, important electrical components that needs to be constantly operated, such as an in-vehicle camera for capturing an image of a vehicle exterior, and an in-vehicle radar for monitoring an obstacle outside the vehicle. Further, such in-vehicle electrical components, that is, loads, usually operate by using power source power supplied from the vehicle.
  • a main battery not only a main battery but also a sub-battery may be provided as an in-vehicle power source. That is, when the power source power cannot be supplied to an important load from the main battery due to a failure of the main battery or the like, it is possible to supply the power source power from the sub-battery instead of the main battery.
  • a battery system control device of Patent Literature JP-A-2016-187235 includes a main battery and a sub-battery. Two switches are connected in series between a power source line on a main battery side and a power source line on a sub-battery side. Therefore, by controlling the two switches, the power source power can be supplied from the main battery to each load, and the power source power can also be supplied from the sub-battery.
  • the power source power is supplied from the main battery side to each load, and the power source line on the sub-battery side is disconnected from the load by the switch. Then, when it is detected that the power from the main battery is interrupted due to some reason, the switch is controlled such that the power source line on the sub-battery side is connected to the load. Therefore, even when the power from the main battery is interrupted, since the source power can be supplied from the sub-battery to the load, function stop of load caused by the interruption of the power source power supply is prevented.
  • a temporal operation delay occurs. That is, a delay from when the power from the main battery is actually interrupted to when a control unit detects the state, and a delay from when the control unit controls the switch to when the switch is actually switched and the source power on the sub-battery side starts to be supplied to the load are considered.
  • the power source power is not supplied to the load for a period from when the power supply from the main battery is interrupted to when the power source power on the sub-battery side starts to be supplied to the load, for example, about several seconds. That is, the load may not function continuously. As a result, a driving assistance function, an automatic driving function, and the like in the automobile may not work continuously.
  • an important load itself has a large capacity capacitor or a large capacity battery incorporated therein, it is possible to avoid function stop during a period from when the power from the main battery is interrupted to when the source power on the sub-battery side starts to be supplied to the load.
  • a large capacity capacitor or battery is large and heavy, it is not desirable to incorporate the capacitor or battery in the load. Further, there is also a concern that the cost of the entire in-vehicle system increases.
  • the present invention has been made in view of the above circumstances, and an object thereof is to provide a power supply system capable of preventing supply of power source power to an important load from being temporarily stopped when a supply source of the power source power to the important load is switched from a main battery side to a sub-battery side due to interruption of power from a main battery or the like.
  • the power supply system according to the present invention is characterized by the following (1) to (5).
  • a power supply system having a main power source, a sub-power source, one or more loads, and a switch configured to control ON/OFF of power supply from the main power source and the sub-power source to the load includes:
  • a first switch which is connected between the main power source and the load and whose ON/OFF is capable of being controlled
  • a second switch which is connected between the sub-power source and the load and whose ON/OFF is capable of being controlled
  • a backflow prevention circuit configured to prevent current backflow between the main power source and the sub-power source
  • the backflow prevention circuit allows current passage in a direction from the sub-power source to the load in a state where at least the second switch is in an off state.
  • the backflow prevention circuit includes a first diode configured to allow current passage in a direction from the main power source to a power source line of the load and to prevent current passage in a reverse direction; and a second diode configured to allow current passage in a direction from the sub-power source to the power source line of the load, and to prevent current passage in a reverse direction,
  • the first switch and the first diode are connected in parallel, and
  • the second switch and the second diode are connected in parallel.
  • At least one of the first diode and the second diode is a body diode parasitized in a semiconductor switch device constituting the first switch and/or the second switch.
  • the power supply system described in the above (1) further includes a power source control unit configured to control ON/OFF of the first switch and ON/OFF of the second switch, and
  • the power source control unit controls ON/OFF of the first switch and ON/OFF of the second switch according to a result of detecting at least one of: a temperature change in a vicinity of the second switch; a current flowing on a main power source side; and a direction of a current in a power source line connected to the load.
  • the load includes one or more sensor devices that contribute to automation of driving of a vehicle.
  • the power supply system having a configuration of the above (1), it is possible to avoid temporarily stopping supply of the power source power to the load when a supply source of the power source power to the load is switched from the main power source side to the sub-power source side due to interruption of power from the main power source, That is, since the backflow prevention circuit allows current passage in a direction from the sub-power source to the load at a timing during a period from when the power from the main power source is interrupted to when the second switch is switched on, the power source power of the sub-power source can be supplied to the load without using a current path of the second switch.
  • the power source power is immediately supplied from the sub-power source side to the load, so that the power supply to the load is not interrupted and function stop in the load does not occur even if it takes time to switch the supply source of the power source power.
  • the first diode allows current passage in the direction from the main power source to the power source line of the load, and prevents current passage in the reverse direction.
  • the second diode allows current passage in the direction from the sub-power source to the power source line of the load, and prevents current passage in the reverse direction.
  • a necessary circuit can be configured with a small number of components.
  • a semiconductor switch device such as a MOS field effect transistor (FET) has a body diode parasitized in a structure thereof, when the body diode is used as the first diode or the second diode, there is no need to add the first diode or the second diode as a new component, so that the number of components can be reduced.
  • FET MOS field effect transistor
  • the power source control unit can grasp the interruption of power from the power source, appropriate control can be performed. For example, when a body diode is used as the second diode, there is a possibility that the body diode generates heat and the temperature rises during energization, and an upper limit of a current value must be severe than usual. However, since the power source control unit performs appropriate control, occurrence of a problem in the body diode can be avoided.
  • the power supply system having a configuration of the above (5), it is possible to prevent occurrence of instantaneous interruption or the like of the power source power supplied to the sensor device. As a result, it can be expected to improve reliability in automation of driving of a vehicle.
  • supply of the power source power to the important load can be prevented from being temporarily stopped when the supply source of the power source power to the important load is switched from the main battery side to the sub-battery side due to interruption of power from the main battery or the like. That is, since the backflow prevention circuit allows current passage in a direction from the sub-power source to the load at a timing during a period from when the power from the main power source is interrupted to when the second switch is switched on, the power source power of the sub-power source can be supplied to the load without using a current path of the second switch.
  • the power source power is immediately supplied from the sub-power source side to the load, so that the power supply to the load is not interrupted and function stop in the load does not occur even if it takes time to switch the supply source of the power source power.
  • FIG. 1 is an electric circuit diagram showing a configuration example of a power supply system according to an embodiment of the present invention.
  • FIG. 2 is a table schematically showing a list of a plurality of states in the power supply system shown in FIG. 1 .
  • FIGS. 3A, 3B and 3C are electric circuit diagrams showing power source current paths in different states of the power supply system shown in FIG. 1 .
  • FIG. 4 is a flowchart showing an operation example of the power supply system shown in FIG. 1 .
  • FIG. 1 is an electric circuit diagram showing a configuration example of a power supply system 10 according to an embodiment of the present invention.
  • the power supply system 10 is configured on an assumption that a function of supplying power source power to loads such as various electrical components is realized on a vehicle such as an automobile.
  • the power supply system 10 of the present embodiment has a special function so as not to interrupt the supply of the power source power including instantaneous interruption to an important load.
  • the power supply system 10 includes an in-vehicle battery 11 as a main power source. Further, a sub-battery 13 is also provided in a case where power from the main power source is interrupted.
  • An alternator (ALT) 12 generates power during operation of the host vehicle and outputs DC power source power. The power source power supplied by the alternator 12 can be used to charge the in-vehicle battery 11 and the sub-battery 13 .
  • a rated power source voltage output from the in-vehicle battery 11 and a rated power source voltage output from the sub-battery 13 are set to about 12V.
  • the output voltage of the in-vehicle battery 11 (for example, 14V) is higher than the output voltage of the sub-battery 13 due to the effect of charging operation or the like.
  • a general load 21 and important loads 22 , 23 exist as loads installed in the host vehicle.
  • the general load 21 corresponds to, for example, a general electrical component such as a vehicle interior lighting lamp, a mirror driving motor, a window opening/closing motor, a door locking motor, a wiper driving motor, and a heater.
  • the important load 22 is an electrical component used for driving operation assistance and automation of driving, and corresponding to, for example, an in-vehicle camera that captures an image of such as a forward direction of the host vehicle or an electronic control unit (ECU) that digitally processes the image to grasp a positional relationship between the host vehicle and a load and to detect an obstacle or the like.
  • an in-vehicle camera that captures an image of such as a forward direction of the host vehicle or an electronic control unit (ECU) that digitally processes the image to grasp a positional relationship between the host vehicle and a load and to detect an obstacle or the like.
  • ECU electronice control unit
  • the important load 23 is an electrical component used for the driving operation assistance and the automation of driving, and corresponding to, for example, a radar for monitoring a surrounding situation such as forward, lateral, or rearward directions of the host vehicle to detect an obstacle or the like.
  • the general load 21 is connected to a power source line 41 , and the important loads 22 , 23 are connected to a power source line 42 . Further, the in-vehicle battery 11 and the alternator 12 are connected to the power source line 41 , and the sub-battery 13 is connected to a power source line 43 .
  • the power source line 41 on a main power source side and the power source line 42 on a load side are connected via a semiconductor switch device 14 .
  • the power source line 43 on a sub-power source side and the power source line 42 are connected via a semiconductor switch device 15 .
  • the semiconductor switch devices 14 , 15 of the present embodiment are both MOS power FETs whose conduction ON/OFF can be controlled. Therefore, the semiconductor switch device 14 includes a body diode 14 a parasitized therein, and the semiconductor switch device 15 also includes a body diode 15 a.
  • the body diode 14 a of the semiconductor switch device 14 is connected with a polarity that conduction in a direction from the power source line 41 on the main power source side to the power source line 42 on the important load side is allowed, and a current in a reverse direction is blocked. Further, the body diode 15 a of the semiconductor switch device 15 is connected with a polarity that conduction in a direction from the power source line 43 on the sub-power source side to the power source line 42 on the important load side is allowed, and a current in a reverse direction is blocked.
  • the body diodes 14 a , 15 a are actively used to realize a special function.
  • a temperature sensor 31 is provided in a vicinity of the semiconductor switch device 15 , The temperature sensor 31 is provided to detect a temperature change caused by heat generation of the body diode 15 a.
  • a current sensor 32 is connected to the power source line 41 on the main power source side.
  • the current sensor 32 is used to detect magnitude of a power source current i 01 flowing from the in-vehicle battery 11 toward the load side.
  • the current sensor 32 can be configured with, for example, a resistor having a very small resistance value and a detector that detects a minute potential difference between both ends of the resistor with high sensitivity.
  • a current sensor 33 is connected to the power source line 42 of the important loads 22 , 23 .
  • the current sensor 33 is used to detect a current flowing direction of a power source current i 02 flowing through the power source line 42 . That is, a state where the power source current i 02 flows from the in-vehicle battery 11 toward the important loads 22 , 23 and a state where the power source current i 02 flows from the sub-battery 13 toward the important loads 22 , 23 are distinguished by the output of the current sensor 33 .
  • the power supply system 10 includes a power source control unit 16 for controlling the entire power supply system 10 .
  • the power source control unit 16 is configured as an electronic control unit including a control element such as a microcomputer.
  • the power source control unit 16 shown in FIG. 1 can control ON/OFF of the semiconductor switch device 14 using a control signal SG 1 . Further, the power source control unit 16 can control ON/OFF of the semiconductor switch device 15 using a control signal SG 2 . By monitoring signals SG 3 , SG 4 and SG 5 , the power source control unit 16 can grasp detection states of the temperature sensor 31 , and the current sensors 32 , 33 , respectively.
  • FIG. 2 is a table schematically showing a list of a plurality of states in the power supply system 10 shown in FIG. 1
  • FIGS. 3A, 3B and 3C are electric circuit diagrams showing power source current paths in different states of the power supply system 10 shown in FIG. 1 .
  • the semiconductor switch device 14 In a normal operating state of the vehicle, the semiconductor switch device 14 is turned on and the semiconductor switch device 15 is turned off as in a “state A” shown in FIG. 2 . Therefore, as shown in FIG. 3A , the power source current i 01 passes through a main body of the semiconductor switch device 14 , and the power source power of the in-vehicle battery 11 is supplied to the important loads 22 , 23 .
  • the voltage of the in-vehicle battery 1 is usually higher than that of the sub-battery 3 , a bias voltage in a reverse direction is applied to the body diode 15 a , and the body diode 15 a prevents current backflow. Since the semiconductor switch device 15 is turned off, a current (i 03 ) does not flow from the sub-battery 3 toward the power source line 42 . As a result, only the main power source supplies power to the important loads 22 , 23 .
  • the body diode 15 a when used for a purpose of causing the power source current i 03 to flow actively, it is necessary to design the body diode 15 a in consideration of a temperature rise caused by heat generation and a limit of the current value in advance.
  • the power source power of the sub-battery 3 is also supplied to the general load 21 via the power source line 43 , the body diode 15 a , the power source line 42 , and the semiconductor switch device 14 .
  • the state transitions from the “state B” to a “state C” in FIG. 2 under the control of the power source control unit 16 .
  • the semiconductor switch device 14 is turned off and the semiconductor switch device 15 is turned on.
  • the power source current i 03 flows to pass through a main body of the semiconductor switch device 15 , and the power source power of the sub-battery 13 is supplied to the important loads 22 , 23 .
  • a resistance value of the main body of the semiconductor switch device 15 in the ON state is smaller than that of the body diode 15 a , the current flowing through the body diode 15 a greatly decreases.
  • the semiconductor switch device 14 is turned off and a bias voltage in a reverse direction is applied to the body diode 14 a , a current in a direction from the power source line 42 to the power source line 41 is prevented, and the power source power supply to the general load 21 is stopped.
  • the power source power supply to the important loads 22 , 23 is not interrupted even when a delay occurs in detection of the interruption of power from the main power source and it takes time to switch the ON/OFF states of the semiconductor switch devices 14 , 15 .
  • FIG. 4 is a flowchart showing an operation example of the power supply system 10 shown in FIG. 1 . Control shown in FIG. 4 is performed by the power source control unit 16 .
  • the power source control unit 16 In an initial state where the power supply from the main power source is not interrupted, the power source control unit 16 outputs the control signals SG 1 , SG 2 in a first step S 11 , the semiconductor switch device 14 on the main power source side is turned on, and the semiconductor switch device 15 on the sub-battery 13 side is turned off. As a result, the “state A” shown in FIG. 2 is obtained. That is, as shown in FIG. 3A , the power source current i 01 flows and the power source power from the in-vehicle battery 11 is supplied to the important loads 22 , 23 .
  • step S 12 the power source control unit 16 monitors states of the signals SG 3 , SG 4 , and SG 5 .
  • the monitoring makes it possible to identify occurrence of interruption of power from the main power source. That is, when the power from the main power source is interrupted, the state transitions from the “state A” to the “state B” in FIG. 2 , and the power source current i 03 flows through the body diode 15 a as shown in FIG. 3B . Therefore, the body diode 15 a generates heat and a temperature increases, so that the change can be detected by the temperature sensor 31 .
  • the power source current i 01 flowing through the power source line 41 greatly decreases. Therefore, by detecting magnitude of the power source current i 01 using the current sensor 32 , occurrence of the interruption of power from the main power source can be identified.
  • the power source control unit 16 Based on the states of the signals SG 3 , SG 4 , and SG 5 monitored in step S 12 , the power source control unit 16 identifies the occurrence of interruption of power from the main power source based on a combination of one or more conditions such as a temperature rise of the body diode 15 a , a decrease in the power source current i 01 flowing through the power source line 41 , and a change in the direction of the current flowing through the power source line 42 . Further, when the interruption of power from the main power source is detected, the process proceeds from step S 13 to step S 14 .
  • step S 14 the power source control unit 16 switches the states of the control signals SG 1 and SG 2 , the semiconductor switch device 14 on the main power source side is turned off, and the semiconductor switch device 15 on the sub-battery 13 side is turned on.
  • the “state C” shown in FIG. 2 is obtained. That is, as shown in FIG. 3C , the power source current i 03 flows through the path passing through the main body of the semiconductor switch device 15 , and the power source power from the sub-battery 3 is supplied to the important loads 22 , 23 .
  • step S 14 since the circuit of the power supply system 10 transits to the “state B” before transiting to the “state C” by the power source control unit 16 executing step S 14 , the power source current i 03 flows through the body diode 15 a as shown in FIG. 3B before step S 14 is executed. Therefore, even when a delay occurs in the execution timing of step S 14 , the power source power supply to the important loads 22 , 23 is not interrupted.
  • the power source control unit 16 monitors the states of the signals SG 3 , SG 4 , and SG 5 in step S 15 . Thus, it is determined whether or not the supply of power from the main power source is restored from the interrupted state.
  • step S 17 the state transitions to the “state A”. That is, the states of the control signals SG 1 and SG 2 are switched, the semiconductor switch device 14 is turned on, and the semiconductor switch device 15 is turned off. Therefore, the state shown in FIG. 3A is obtained, and the power source power from the in-vehicle battery 11 is supplied again to the important loads 22 , 23 via the power source line 41 , the semiconductor switch device 14 , and the power source line 42 .
  • the body diode 14 a is biased by a voltage in the forward direction, and the power source current i 01 flows through the body diode 14 a even when the semiconductor switch device 14 is turned off.
  • the power source power supply to the important loads 22 , 23 can be prevented from being interrupted temporarily. That is, since the power source current i 03 flows through the path of the body diode 15 a , as shown in FIG. 3B , even at the timing before the power source control unit 16 switches on the semiconductor switch device 15 , the power source power of the sub-battery 3 can be immediately supplied to the important loads 22 , 23 .
  • the power source control unit 16 switches on the semiconductor switch device 15 , and thus continuation of heat generation of the body diode 15 a can be avoided. Further, by switching off the semiconductor switch device 14 , the power source power of the sub-battery 13 can be prevented from flowing toward the power source line 41 side and the time before the power source power of the sub-battery 13 is consumed can be extended.
  • the power source control unit 16 detects the temperature change in a vicinity of the body diode 15 a , the magnitude of the power source current i 01 flowing through the power source line 41 , and the direction of the power source current i 02 flowing through the power source line 42 , the occurrence of interruption of power from the main power source can be identified correctly.
  • Each of the semiconductor switch devices 14 , 15 shown in FIG. 1 may be replaced by a component other than the semiconductor switch device, such as a mechanical relay. However, in that case, it is necessary to connect a new component having a function equivalent to each of the body diodes 14 a and 15 a , that is, a diode in parallel with each contact point.
  • adopting the semiconductor switch devices 14 , 15 as shown in FIG. 1 is advantageous in reducing the number of components, and reducing the size and weight.
  • the occurrence of interruption of power from the main power source can be identified by just monitoring any one of the signals SG 3 to SG 5 monitored in step S 12 of FIG. 4 by the power source control unit 16 .
  • the occurrence of interruption of power from the main power source may be identified based on an appropriate combination of a plurality of states of the signals SG 3 to SG 5 .
  • a first switch semiconductor switch device 14 which is connected between the main power source and the load and whose ON/OFF is capable of being controlled;
  • a second switch semiconductor switch device 15 which is connected between the sub-power source and the load and whose ON/OFF is capable of being controlled;
  • a backflow prevention circuit (body diodes 14 a , 15 a ) configured to prevent current backflow between the main power source and the sub-power source, and
  • the backflow prevention circuit (body diode 15 a ) allows current passage in a direction from the sub-power source to the load in a state where at least the second switch is in an off state.
  • the backflow prevention circuit includes a first diode (body diode 14 a ) configured to allow current passage in a direction from the main power source to a power source line of the load and to prevent current passage in a reverse direction; and a second diode (body diode 15 a ) configured to allow current passage in a direction from the sub-power source to the power source line of the load, and to prevent current passage in a reverse direction,
  • the first switch and the first diode are connected in parallel, and
  • the second switch and the second diode are connected in parallel.
  • the power source control unit controls ON/OFF of the first switch and ON/OFF of the second switch (S 12 to S 14 ) according to a result of detecting at least one of: a temperature change in a vicinity of the second switch; a current flowing on a main power source side; and a direction of a current in a power source line connected to the load.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Transportation (AREA)
  • Emergency Management (AREA)
  • Business, Economics & Management (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Direct Current Feeding And Distribution (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)
  • Stand-By Power Supply Arrangements (AREA)
  • Secondary Cells (AREA)

Abstract

A power supply system includes; a first switch connected between a main power source and loads; a second switch connected between a sub-battery and the loads; and backflow prevention circuit that prevent current backflow between the main power source and the sub-battery, and polarity of the backflow prevention circuit is devised so as to allow current passage in a direction from the sub-power source to the loads even when the second switch is in an off state. When power from the main power source is interrupted, the power source power of the sub-power source is supplied to the loads via the backflow prevention circuit even the second switch remains in the off state, so that the power supply is not interrupted.

Description

CROSS REFERENCE TO RELATED APPLICATIONS
This application is based on and claims priority from Japanese patent application No. 2019-083806 filed on Apr. 25, 2019, the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION 1. Technical Field
The present invention relates to a power supply system that is available, for example, to provide power to an important load in an in-vehicle system.
2. Background Art
A vehicle such as an automobile has various functions for realizing stable traveling. Further, for example, more advanced functions such as driving operation assistance of a driver or automation of driving may be installed, and more and more advanced functions tend to be added in the future.
The in-vehicle system for realizing such advanced functions includes, for example, important electrical components that needs to be constantly operated, such as an in-vehicle camera for capturing an image of a vehicle exterior, and an in-vehicle radar for monitoring an obstacle outside the vehicle. Further, such in-vehicle electrical components, that is, loads, usually operate by using power source power supplied from the vehicle.
Therefore, in a power supply system installed in the vehicle, it is required that supply of the power source power is not interrupted particularly for an important load. Accordingly, for example, in a vehicle provided with the advanced functions, not only a main battery but also a sub-battery may be provided as an in-vehicle power source. That is, when the power source power cannot be supplied to an important load from the main battery due to a failure of the main battery or the like, it is possible to supply the power source power from the sub-battery instead of the main battery.
For example, a battery system control device of Patent Literature JP-A-2016-187235 includes a main battery and a sub-battery. Two switches are connected in series between a power source line on a main battery side and a power source line on a sub-battery side. Therefore, by controlling the two switches, the power source power can be supplied from the main battery to each load, and the power source power can also be supplied from the sub-battery.
SUMMARY
In a general in-vehicle system including a main battery and a sub-battery, normally, the power source power is supplied from the main battery side to each load, and the power source line on the sub-battery side is disconnected from the load by the switch. Then, when it is detected that the power from the main battery is interrupted due to some reason, the switch is controlled such that the power source line on the sub-battery side is connected to the load. Therefore, even when the power from the main battery is interrupted, since the source power can be supplied from the sub-battery to the load, function stop of load caused by the interruption of the power source power supply is prevented.
However, when a supply source of the power source power to be supplied to the important load is switched from the main battery side to the sub-battery side, a temporal operation delay occurs. That is, a delay from when the power from the main battery is actually interrupted to when a control unit detects the state, and a delay from when the control unit controls the switch to when the switch is actually switched and the source power on the sub-battery side starts to be supplied to the load are considered.
Therefore, the power source power is not supplied to the load for a period from when the power supply from the main battery is interrupted to when the power source power on the sub-battery side starts to be supplied to the load, for example, about several seconds. That is, the load may not function continuously. As a result, a driving assistance function, an automatic driving function, and the like in the automobile may not work continuously.
For example, if an important load itself has a large capacity capacitor or a large capacity battery incorporated therein, it is possible to avoid function stop during a period from when the power from the main battery is interrupted to when the source power on the sub-battery side starts to be supplied to the load. However, since a large capacity capacitor or battery is large and heavy, it is not desirable to incorporate the capacitor or battery in the load. Further, there is also a concern that the cost of the entire in-vehicle system increases.
The present invention has been made in view of the above circumstances, and an object thereof is to provide a power supply system capable of preventing supply of power source power to an important load from being temporarily stopped when a supply source of the power source power to the important load is switched from a main battery side to a sub-battery side due to interruption of power from a main battery or the like.
Solution to Problem
In order to achieve the above object, the power supply system according to the present invention is characterized by the following (1) to (5).
(1) A power supply system having a main power source, a sub-power source, one or more loads, and a switch configured to control ON/OFF of power supply from the main power source and the sub-power source to the load, includes:
a first switch which is connected between the main power source and the load and whose ON/OFF is capable of being controlled;
a second switch which is connected between the sub-power source and the load and whose ON/OFF is capable of being controlled; and
a backflow prevention circuit configured to prevent current backflow between the main power source and the sub-power source, and
the backflow prevention circuit allows current passage in a direction from the sub-power source to the load in a state where at least the second switch is in an off state.
(2) In the power supply system descried in the above (1), the backflow prevention circuit includes a first diode configured to allow current passage in a direction from the main power source to a power source line of the load and to prevent current passage in a reverse direction; and a second diode configured to allow current passage in a direction from the sub-power source to the power source line of the load, and to prevent current passage in a reverse direction,
the first switch and the first diode are connected in parallel, and
the second switch and the second diode are connected in parallel.
(3) In the power supply system described in the above (2), at least one of the first diode and the second diode is a body diode parasitized in a semiconductor switch device constituting the first switch and/or the second switch.
(4) The power supply system described in the above (1) further includes a power source control unit configured to control ON/OFF of the first switch and ON/OFF of the second switch, and
the power source control unit controls ON/OFF of the first switch and ON/OFF of the second switch according to a result of detecting at least one of: a temperature change in a vicinity of the second switch; a current flowing on a main power source side; and a direction of a current in a power source line connected to the load.
(5) In the power supply system described in the above (1), the load includes one or more sensor devices that contribute to automation of driving of a vehicle.
According to the power supply system having a configuration of the above (1), it is possible to avoid temporarily stopping supply of the power source power to the load when a supply source of the power source power to the load is switched from the main power source side to the sub-power source side due to interruption of power from the main power source, That is, since the backflow prevention circuit allows current passage in a direction from the sub-power source to the load at a timing during a period from when the power from the main power source is interrupted to when the second switch is switched on, the power source power of the sub-power source can be supplied to the load without using a current path of the second switch. In other words, when the power from the main power source is interrupted, the power source power is immediately supplied from the sub-power source side to the load, so that the power supply to the load is not interrupted and function stop in the load does not occur even if it takes time to switch the supply source of the power source power.
According to the power supply system having a configuration of the above (2), the first diode allows current passage in the direction from the main power source to the power source line of the load, and prevents current passage in the reverse direction. The second diode allows current passage in the direction from the sub-power source to the power source line of the load, and prevents current passage in the reverse direction. Further, since the first switch and the first diode are connected in parallel, a current can flow in a forward direction of the first diode and power can be supplied to the load even when the first switch is in an off state. Further, since the second switch and the second diode are connected in parallel, a current can flow in a forward direction of the second diode and power can be supplied to the load even when the second switch is in an off state.
According to the power supply system having a configuration of the above (3), a necessary circuit can be configured with a small number of components. For example, since a semiconductor switch device such as a MOS field effect transistor (FET) has a body diode parasitized in a structure thereof, when the body diode is used as the first diode or the second diode, there is no need to add the first diode or the second diode as a new component, so that the number of components can be reduced.
According to the power supply system having a configuration of the above (4), since the power source control unit can grasp the interruption of power from the power source, appropriate control can be performed. For example, when a body diode is used as the second diode, there is a possibility that the body diode generates heat and the temperature rises during energization, and an upper limit of a current value must be severe than usual. However, since the power source control unit performs appropriate control, occurrence of a problem in the body diode can be avoided.
According to the power supply system having a configuration of the above (5), it is possible to prevent occurrence of instantaneous interruption or the like of the power source power supplied to the sensor device. As a result, it can be expected to improve reliability in automation of driving of a vehicle.
According to the power supply system of the present invention, supply of the power source power to the important load can be prevented from being temporarily stopped when the supply source of the power source power to the important load is switched from the main battery side to the sub-battery side due to interruption of power from the main battery or the like. That is, since the backflow prevention circuit allows current passage in a direction from the sub-power source to the load at a timing during a period from when the power from the main power source is interrupted to when the second switch is switched on, the power source power of the sub-power source can be supplied to the load without using a current path of the second switch. In other words, when interruption of power from the main power source occurs, the power source power is immediately supplied from the sub-power source side to the load, so that the power supply to the load is not interrupted and function stop in the load does not occur even if it takes time to switch the supply source of the power source power.
The present invention has been briefly described above. Further, details of the present invention will be clarified by reading a mode (hereinafter, referred to as “embodiment”) for carrying out the invention to be described below with reference to attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an electric circuit diagram showing a configuration example of a power supply system according to an embodiment of the present invention.
FIG. 2 is a table schematically showing a list of a plurality of states in the power supply system shown in FIG. 1.
FIGS. 3A, 3B and 3C are electric circuit diagrams showing power source current paths in different states of the power supply system shown in FIG. 1.
FIG. 4 is a flowchart showing an operation example of the power supply system shown in FIG. 1.
 DETAILED DESCRIPTION OF EMBODIMENTS
A specific embodiment according to the present invention will be described below with reference to the drawings.
FIG. 1 is an electric circuit diagram showing a configuration example of a power supply system 10 according to an embodiment of the present invention.
The power supply system 10 according to the present embodiment is configured on an assumption that a function of supplying power source power to loads such as various electrical components is realized on a vehicle such as an automobile. In particular, the power supply system 10 of the present embodiment has a special function so as not to interrupt the supply of the power source power including instantaneous interruption to an important load.
The power supply system 10 includes an in-vehicle battery 11 as a main power source. Further, a sub-battery 13 is also provided in a case where power from the main power source is interrupted. An alternator (ALT) 12 generates power during operation of the host vehicle and outputs DC power source power. The power source power supplied by the alternator 12 can be used to charge the in-vehicle battery 11 and the sub-battery 13.
As an example, a rated power source voltage output from the in-vehicle battery 11 and a rated power source voltage output from the sub-battery 13 are set to about 12V. The output voltage of the in-vehicle battery 11 (for example, 14V) is higher than the output voltage of the sub-battery 13 due to the effect of charging operation or the like.
In the example shown in FIG. 1, a general load 21, and important loads 22, 23 exist as loads installed in the host vehicle. The general load 21 corresponds to, for example, a general electrical component such as a vehicle interior lighting lamp, a mirror driving motor, a window opening/closing motor, a door locking motor, a wiper driving motor, and a heater.
The important load 22 is an electrical component used for driving operation assistance and automation of driving, and corresponding to, for example, an in-vehicle camera that captures an image of such as a forward direction of the host vehicle or an electronic control unit (ECU) that digitally processes the image to grasp a positional relationship between the host vehicle and a load and to detect an obstacle or the like.
The important load 23 is an electrical component used for the driving operation assistance and the automation of driving, and corresponding to, for example, a radar for monitoring a surrounding situation such as forward, lateral, or rearward directions of the host vehicle to detect an obstacle or the like.
If functions of the important loads 22, 23 are stopped even for a short period of time, grasping of the driving situation may be adversely affected and the reliability of the automatic driving and the like may be reduced. Therefore, it is necessary to prevent instantaneous interruption of power supply to the important loads 22, 23 during switching of a supply source of the power source power.
In the example shown in FIG. 1, the general load 21 is connected to a power source line 41, and the important loads 22, 23 are connected to a power source line 42. Further, the in-vehicle battery 11 and the alternator 12 are connected to the power source line 41, and the sub-battery 13 is connected to a power source line 43.
The power source line 41 on a main power source side and the power source line 42 on a load side are connected via a semiconductor switch device 14. The power source line 43 on a sub-power source side and the power source line 42 are connected via a semiconductor switch device 15.
As shown in FIG. 1, the semiconductor switch devices 14, 15 of the present embodiment are both MOS power FETs whose conduction ON/OFF can be controlled. Therefore, the semiconductor switch device 14 includes a body diode 14 a parasitized therein, and the semiconductor switch device 15 also includes a body diode 15 a.
The body diode 14 a of the semiconductor switch device 14 is connected with a polarity that conduction in a direction from the power source line 41 on the main power source side to the power source line 42 on the important load side is allowed, and a current in a reverse direction is blocked. Further, the body diode 15 a of the semiconductor switch device 15 is connected with a polarity that conduction in a direction from the power source line 43 on the sub-power source side to the power source line 42 on the important load side is allowed, and a current in a reverse direction is blocked. In the power supply system 10 of the present embodiment, unlike a general circuit configuration, the body diodes 14 a, 15 a are actively used to realize a special function.
As shown in FIG. 1, a temperature sensor 31 is provided in a vicinity of the semiconductor switch device 15, The temperature sensor 31 is provided to detect a temperature change caused by heat generation of the body diode 15 a.
A current sensor 32 is connected to the power source line 41 on the main power source side. The current sensor 32 is used to detect magnitude of a power source current i01 flowing from the in-vehicle battery 11 toward the load side. The current sensor 32 can be configured with, for example, a resistor having a very small resistance value and a detector that detects a minute potential difference between both ends of the resistor with high sensitivity.
Further, a current sensor 33 is connected to the power source line 42 of the important loads 22, 23. The current sensor 33 is used to detect a current flowing direction of a power source current i02 flowing through the power source line 42. That is, a state where the power source current i02 flows from the in-vehicle battery 11 toward the important loads 22, 23 and a state where the power source current i02 flows from the sub-battery 13 toward the important loads 22, 23 are distinguished by the output of the current sensor 33.
The power supply system 10 includes a power source control unit 16 for controlling the entire power supply system 10. The power source control unit 16 is configured as an electronic control unit including a control element such as a microcomputer.
The power source control unit 16 shown in FIG. 1 can control ON/OFF of the semiconductor switch device 14 using a control signal SG1. Further, the power source control unit 16 can control ON/OFF of the semiconductor switch device 15 using a control signal SG2. By monitoring signals SG3, SG4 and SG5, the power source control unit 16 can grasp detection states of the temperature sensor 31, and the current sensors 32, 33, respectively.
FIG. 2 is a table schematically showing a list of a plurality of states in the power supply system 10 shown in FIG. 1, Further, FIGS. 3A, 3B and 3C are electric circuit diagrams showing power source current paths in different states of the power supply system 10 shown in FIG. 1.
[State A]
In a normal operating state of the vehicle, the semiconductor switch device 14 is turned on and the semiconductor switch device 15 is turned off as in a “state A” shown in FIG. 2. Therefore, as shown in FIG. 3A, the power source current i01 passes through a main body of the semiconductor switch device 14, and the power source power of the in-vehicle battery 11 is supplied to the important loads 22, 23.
Further, since the voltage of the in-vehicle battery 1 is usually higher than that of the sub-battery 3, a bias voltage in a reverse direction is applied to the body diode 15 a, and the body diode 15 a prevents current backflow. Since the semiconductor switch device 15 is turned off, a current (i03) does not flow from the sub-battery 3 toward the power source line 42. As a result, only the main power source supplies power to the important loads 22, 23.
[State B]
When the power from the main power source is interrupted due to some reason, a predetermined power source voltage does not appear in the power source line 41. However, it is difficult to instantaneously grasp occurrence of interruption of power from the main power source, and a “state B” shown in FIG. 2 is obtained immediately after the power from the main power source is interrupted. In the “state B”, the semiconductor switch device 14 is also turned on and the semiconductor switch device 15 is kept off similarly to the “state A”.
However, when a voltage of the power source line 42 decreases and is lower than the voltage of the sub-battery 13, a bias voltage in a forward direction is applied to the body diode 15 a, and the body diode 15 a is brought into a conductive state. Therefore, as shown in FIG. 3B, the power source current i03 flows through a path passing through the body diode 15 a, and the power source power of the sub-battery 13 is supplied to the important loads 22, 23.
That is, when the interruption of the power from the main power source occurs, the state transitions from the “state A” to the “state B”, so that the power source power of the sub-battery 13 can be supplied to the important loads 22, 23 without switching the states of the semiconductor switch devices 14, 15. Therefore, even when the power from the main power source is interrupted, the important loads 22, 23 can operate continuously.
Accordingly, when the body diode 15 a is used for a purpose of causing the power source current i03 to flow actively, it is necessary to design the body diode 15 a in consideration of a temperature rise caused by heat generation and a limit of the current value in advance.
Since the semiconductor switch device 14 is turned on in the “state B”, the power source power of the sub-battery 3 is also supplied to the general load 21 via the power source line 43, the body diode 15 a, the power source line 42, and the semiconductor switch device 14.
[State C]
When the power source control unit 16 shown in FIG. 1 detects interruption of power from the main power source, the state transitions from the “state B” to a “state C” in FIG. 2 under the control of the power source control unit 16. In the “state C”, as shown in FIG. 2, the semiconductor switch device 14 is turned off and the semiconductor switch device 15 is turned on.
Therefore, as shown in FIG. 3C, the power source current i03 flows to pass through a main body of the semiconductor switch device 15, and the power source power of the sub-battery 13 is supplied to the important loads 22, 23. In this case, since a resistance value of the main body of the semiconductor switch device 15 in the ON state is smaller than that of the body diode 15 a, the current flowing through the body diode 15 a greatly decreases.
Further, since the semiconductor switch device 14 is turned off and a bias voltage in a reverse direction is applied to the body diode 14 a, a current in a direction from the power source line 42 to the power source line 41 is prevented, and the power source power supply to the general load 21 is stopped.
As described above, when the power from the main power source is interrupted, since the state of the power supply system 10 transitions from the “state A” to the “state C” via the “state B”, the power source power supply to the important loads 22, 23 is not interrupted even when a delay occurs in detection of the interruption of power from the main power source and it takes time to switch the ON/OFF states of the semiconductor switch devices 14, 15.
[Operation of Power Supply System]
FIG. 4 is a flowchart showing an operation example of the power supply system 10 shown in FIG. 1. Control shown in FIG. 4 is performed by the power source control unit 16.
In an initial state where the power supply from the main power source is not interrupted, the power source control unit 16 outputs the control signals SG1, SG2 in a first step S11, the semiconductor switch device 14 on the main power source side is turned on, and the semiconductor switch device 15 on the sub-battery 13 side is turned off. As a result, the “state A” shown in FIG. 2 is obtained. That is, as shown in FIG. 3A, the power source current i01 flows and the power source power from the in-vehicle battery 11 is supplied to the important loads 22, 23.
In step S12, the power source control unit 16 monitors states of the signals SG3, SG4, and SG5. The monitoring makes it possible to identify occurrence of interruption of power from the main power source. That is, when the power from the main power source is interrupted, the state transitions from the “state A” to the “state B” in FIG. 2, and the power source current i03 flows through the body diode 15 a as shown in FIG. 3B. Therefore, the body diode 15 a generates heat and a temperature increases, so that the change can be detected by the temperature sensor 31.
Further, since the state is changed from the state of FIG. 3A to the state of FIG. 3B when the power from the main power source is interrupted, the power source current i01 flowing through the power source line 41 greatly decreases. Therefore, by detecting magnitude of the power source current i01 using the current sensor 32, occurrence of the interruption of power from the main power source can be identified.
Further, since the state is changed from the state of FIG. 3A to the state of FIG. 3B when the interruption of power from the main power source occurs, a direction of the current flowing through the power source line 42 changes accordingly. Therefore, by detecting the direction of the current in the power source line 42 using the current sensor 33, the occurrence of interruption of power from the main power source can be identified.
Based on the states of the signals SG3, SG4, and SG5 monitored in step S12, the power source control unit 16 identifies the occurrence of interruption of power from the main power source based on a combination of one or more conditions such as a temperature rise of the body diode 15 a, a decrease in the power source current i01 flowing through the power source line 41, and a change in the direction of the current flowing through the power source line 42. Further, when the interruption of power from the main power source is detected, the process proceeds from step S13 to step S14.
In step S14, the power source control unit 16 switches the states of the control signals SG1 and SG2, the semiconductor switch device 14 on the main power source side is turned off, and the semiconductor switch device 15 on the sub-battery 13 side is turned on. As a result, the “state C” shown in FIG. 2 is obtained. That is, as shown in FIG. 3C, the power source current i03 flows through the path passing through the main body of the semiconductor switch device 15, and the power source power from the sub-battery 3 is supplied to the important loads 22, 23.
As a matter of course, since the circuit of the power supply system 10 transits to the “state B” before transiting to the “state C” by the power source control unit 16 executing step S14, the power source current i03 flows through the body diode 15 a as shown in FIG. 3B before step S14 is executed. Therefore, even when a delay occurs in the execution timing of step S14, the power source power supply to the important loads 22, 23 is not interrupted.
After the transition to the “state C”, the power source control unit 16 monitors the states of the signals SG3, SG4, and SG5 in step S15. Thus, it is determined whether or not the supply of power from the main power source is restored from the interrupted state.
When the main power source is restored to the normal state, the power source control unit 16 proceeds to step S17 from step S16 and the state transitions to the “state A”. That is, the states of the control signals SG1 and SG2 are switched, the semiconductor switch device 14 is turned on, and the semiconductor switch device 15 is turned off. Therefore, the state shown in FIG. 3A is obtained, and the power source power from the in-vehicle battery 11 is supplied again to the important loads 22, 23 via the power source line 41, the semiconductor switch device 14, and the power source line 42.
Even before the power source control unit 16 switches the state from the state of FIG. 3C to the state of FIG. 3A under the control of step S17, since the power source current i01 flows when the main power source is restored, the power source power supply to the important loads 22, 23 is not interrupted during the switching.
That is, when the main power source is restored, since the voltage of the power source line 41 is higher than that of the power source line 42, the body diode 14 a is biased by a voltage in the forward direction, and the power source current i01 flows through the body diode 14 a even when the semiconductor switch device 14 is turned off.
As described above, in the power supply system 10 according to the present embodiment, when the power from the main power source is interrupted due to a failure of the in-vehicle battery 11 and the like, the power source power supply to the important loads 22, 23 can be prevented from being interrupted temporarily. That is, since the power source current i03 flows through the path of the body diode 15 a, as shown in FIG. 3B, even at the timing before the power source control unit 16 switches on the semiconductor switch device 15, the power source power of the sub-battery 3 can be immediately supplied to the important loads 22, 23.
Therefore, it is possible to improve the reliability of the power source power supply to the important loads 22, 23 used for the driving assistance and the automatic driving, such as an in-vehicle camera and a radar, and to improve safety in the vehicle driving.
In addition, when the power from the main power source is interrupted, the power source control unit 16 switches on the semiconductor switch device 15, and thus continuation of heat generation of the body diode 15 a can be avoided. Further, by switching off the semiconductor switch device 14, the power source power of the sub-battery 13 can be prevented from flowing toward the power source line 41 side and the time before the power source power of the sub-battery 13 is consumed can be extended.
Further, the power source control unit 16 detects the temperature change in a vicinity of the body diode 15 a, the magnitude of the power source current i01 flowing through the power source line 41, and the direction of the power source current i02 flowing through the power source line 42, the occurrence of interruption of power from the main power source can be identified correctly.
Each of the semiconductor switch devices 14, 15 shown in FIG. 1, for example, may be replaced by a component other than the semiconductor switch device, such as a mechanical relay. However, in that case, it is necessary to connect a new component having a function equivalent to each of the body diodes 14 a and 15 a, that is, a diode in parallel with each contact point. However, adopting the semiconductor switch devices 14, 15 as shown in FIG. 1 is advantageous in reducing the number of components, and reducing the size and weight.
The occurrence of interruption of power from the main power source can be identified by just monitoring any one of the signals SG3 to SG5 monitored in step S12 of FIG. 4 by the power source control unit 16. The occurrence of interruption of power from the main power source may be identified based on an appropriate combination of a plurality of states of the signals SG3 to SG5.
Here, features of the power supply system according to the embodiment of the present invention described above will be briefly summarized in the following [1] to [5].
[1] A power supply system (10) having a main power source (in-vehicle battery 11), a sub-power source (sub-battery 13), one or more loads (important loads 22, 23), and a switch configured to control ON/OFF of power supply from the main power source and the sub-power source to the load, including:
a first switch (semiconductor switch device 14) which is connected between the main power source and the load and whose ON/OFF is capable of being controlled;
a second switch (semiconductor switch device 15) which is connected between the sub-power source and the load and whose ON/OFF is capable of being controlled; and
a backflow prevention circuit ( body diodes 14 a, 15 a) configured to prevent current backflow between the main power source and the sub-power source, and
the backflow prevention circuit (body diode 15 a) allows current passage in a direction from the sub-power source to the load in a state where at least the second switch is in an off state.
[2] The power supply system according to the above [1], wherein the backflow prevention circuit includes a first diode (body diode 14 a) configured to allow current passage in a direction from the main power source to a power source line of the load and to prevent current passage in a reverse direction; and a second diode (body diode 15 a) configured to allow current passage in a direction from the sub-power source to the power source line of the load, and to prevent current passage in a reverse direction,
the first switch and the first diode are connected in parallel, and
the second switch and the second diode are connected in parallel.
[3] The power supply system according to the above [2], wherein at least one of the first diode and the second diode is a body diode (14 a, 15 a) parasitized in a semiconductor switch device (14, 15) constituting the first switch and/or the second switch.
[4] The power supply system according to any one of the above [1] to [3], further including a power source control unit (16) configured to control ON/OFF of the first switch and ON/OFF of the second switch, and
the power source control unit controls ON/OFF of the first switch and ON/OFF of the second switch (S12 to S14) according to a result of detecting at least one of: a temperature change in a vicinity of the second switch; a current flowing on a main power source side; and a direction of a current in a power source line connected to the load.
[5] The power supply system according to any one of the above [1] to [4], wherein the load includes one or more sensor devices (important loads 22, 23) that contribute to automation of driving of a vehicle.

Claims (5)

What is claimed is:
1. A power supply system comprising:
a main power source;
a sub-power source;
one or more loads;
a switch assembly configured to control ON/OFF of power supply from the main power source and the sub-power source to the load, the switch assembly including:
a first switch which is connected between the main power source and the load and whose ON/OFF is capable of being controlled;
a second switch which is connected between the sub-power source and the load and whose ON/OFF is capable of being controlled; and
a backflow prevention circuit configured to prevent current backflow between the main power source and the sub-power source, the backflow prevention circuit allows current passage in a direction from the sub-power source to the load in a state where at least the second switch is in an off state; and
a power source control unit configured to control ON/OFF of the first switch and ON/OFF of the second switch,
the power source control unit being configured to,
determine an interruption of power supplied by the main power source according to a result of detecting each of: a temperature change in a vicinity of the second switch; a current flowing on a main power source side; and a direction of a current in a power source line connected to the load when the first switch is an on state and the second switch is in the off state,
change the first switch from the on state to the off state and the second switch from the off state to the on state when the power source controller determines the interruption of power.
2. The power supply system according to claim 1, wherein the backflow prevention circuit includes a first diode configured to allow current passage in a direction from the main power source to at power source line of the load and to prevent current passage in a reverse direction; and a second diode configured to allow current passage in a direction from the sub-power source to the power source line of the load, and to prevent current passage in a reverse direction,
the first switch and the first diode are connected in parallel, and
the second switch and the second diode are connected in parallel.
3. The power supply system according to claim 2, wherein at least one of the first diode and the second diode is a body diode parasitized in a semiconductor switch device constituting the first switch and/or the second switch.
4. The power supply system according to claim 1, wherein the load includes one or more sensor devices that contribute to automation of driving of a vehicle.
5. The power supply system according to claim 1, wherein the power source controller is configured to,
determine a restoration of power supplied by the main power source according to a result of detecting a current flowing on a main power source side, when the first switch is in the off state and the second switch is in the on state, and
change the first switch from the off state to the on state and the second switch from the on state to the off state when the power source controller determines the restoration of power.
US16/828,892 2019-04-25 2020-03-24 Power supply system Active US11201498B2 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2019-083806 2019-04-25
JP2019083806A JP7074717B2 (en) 2019-04-25 2019-04-25 Power supply system
JPJP2019-083806 2019-04-25

Publications (2)

Publication Number Publication Date
US20200343763A1 US20200343763A1 (en) 2020-10-29
US11201498B2 true US11201498B2 (en) 2021-12-14

Family

ID=69960393

Family Applications (1)

Application Number Title Priority Date Filing Date
US16/828,892 Active US11201498B2 (en) 2019-04-25 2020-03-24 Power supply system

Country Status (4)

Country Link
US (1) US11201498B2 (en)
EP (1) EP3730349B1 (en)
JP (1) JP7074717B2 (en)
CN (1) CN111864881B (en)

Families Citing this family (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11338769B2 (en) * 2020-05-21 2022-05-24 Verizon Connect Development Limited Systems and methods for immobilizing a vehicle
CN112467868B (en) * 2020-12-03 2024-05-31 芜湖华沅微电子有限公司 Multi-path power supply switching circuit and method
CN113306512A (en) * 2021-03-28 2021-08-27 重庆长安汽车股份有限公司 Finished automobile power distribution system and method and automobile
JP7468442B2 (en) * 2021-04-12 2024-04-16 株式会社デンソー Power System
CN113602214B (en) * 2021-07-08 2023-09-12 东风汽车股份有限公司 Intelligent control electromagnetic power supply main switch control system and method
FR3126355A1 (en) * 2021-08-27 2023-03-03 Psa Automobiles Sa Method for saving electrical energy for a motor vehicle, associated electronic device and vehicle
CN114750715A (en) * 2021-12-06 2022-07-15 广州汽车集团股份有限公司 Power management system, management method and device thereof and vehicle
WO2023224495A1 (en) * 2022-05-19 2023-11-23 Hagal Technology AS Variable battery energy management system
DE112022004530T5 (en) 2022-05-24 2024-07-25 Autonetworks Technologies, Ltd. POWER SUPPLY CONTROL DEVICE
US20240001767A1 (en) * 2022-07-01 2024-01-04 Ferrari S.P.A. Electrical system of a road vehicle provided with a dc-dc electronic power converter and related road vehicle
WO2024241475A1 (en) * 2023-05-23 2024-11-28 株式会社オートネットワーク技術研究所 Onboard cutoff device

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6304054B1 (en) * 1998-09-02 2001-10-16 Scania Cv Aktiebolag Electrical system for motor vehicles
US20090230923A1 (en) * 2008-03-14 2009-09-17 Eveready Battery Company, Inc. Battery management circuit
JP2016187236A (en) 2015-03-27 2016-10-27 矢崎総業株式会社 Battery system control device
JP2016187235A (en) 2015-03-27 2016-10-27 矢崎総業株式会社 Battery system control device
US20160368437A1 (en) * 2014-02-19 2016-12-22 Continental Automotive Gmbh Controlled Connection Of Multiple Wiring System Branches Of A Vehicle
US20180004237A1 (en) * 2016-07-01 2018-01-04 Yazaki Corporation Semiconductor switch control device
US20190123545A1 (en) * 2016-04-15 2019-04-25 Autonetworks Technologies, Ltd. Relay device
US20190237988A1 (en) * 2016-05-31 2019-08-01 Autonetworks Technologies, Ltd. Relay device and power supply device

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2776493B2 (en) * 1994-08-12 1998-07-16 インターナショナル・ビジネス・マシーンズ・コーポレイション Power supply device for electronic equipment and control method thereof
JP2002112469A (en) * 2000-09-29 2002-04-12 Allied Tereshisu Kk Or circuit consisting of field-effect transistors and power supply using it
DE102010004644A1 (en) * 2010-01-13 2011-07-14 Phoenix Contact GmbH & Co. KG, 32825 Redundancy module with symmetrical current paths
JP6135333B2 (en) * 2013-06-28 2017-05-31 ソニー株式会社 Power supply switching circuit, electronic device, and control method for power supply switching circuit
JP5619253B1 (en) * 2013-10-15 2014-11-05 三菱電機株式会社 Inductive load power supply control device
JP2017069716A (en) * 2015-09-29 2017-04-06 株式会社オートネットワーク技術研究所 Semiconductor device and control device
JP6597371B2 (en) * 2016-02-17 2019-10-30 株式会社オートネットワーク技術研究所 In-vehicle power supply switch device and in-vehicle power supply device
KR20170116697A (en) * 2016-04-12 2017-10-20 주식회사 엘지화학 Fail-safe control apparatus of the connection switch for the applicable High-voltage at the time of discharge
JP6777849B2 (en) * 2016-07-13 2020-10-28 ミツミ電機株式会社 Charging control circuit for in-vehicle charging connector, in-vehicle charging connector, and in-vehicle data transfer / charging system to external devices

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6304054B1 (en) * 1998-09-02 2001-10-16 Scania Cv Aktiebolag Electrical system for motor vehicles
US20090230923A1 (en) * 2008-03-14 2009-09-17 Eveready Battery Company, Inc. Battery management circuit
US20160368437A1 (en) * 2014-02-19 2016-12-22 Continental Automotive Gmbh Controlled Connection Of Multiple Wiring System Branches Of A Vehicle
JP2016187236A (en) 2015-03-27 2016-10-27 矢崎総業株式会社 Battery system control device
JP2016187235A (en) 2015-03-27 2016-10-27 矢崎総業株式会社 Battery system control device
US20190123545A1 (en) * 2016-04-15 2019-04-25 Autonetworks Technologies, Ltd. Relay device
US20190237988A1 (en) * 2016-05-31 2019-08-01 Autonetworks Technologies, Ltd. Relay device and power supply device
US20180004237A1 (en) * 2016-07-01 2018-01-04 Yazaki Corporation Semiconductor switch control device

Also Published As

Publication number Publication date
CN111864881A (en) 2020-10-30
CN111864881B (en) 2024-03-19
EP3730349B1 (en) 2022-02-02
JP2020182318A (en) 2020-11-05
US20200343763A1 (en) 2020-10-29
EP3730349A1 (en) 2020-10-28
JP7074717B2 (en) 2022-05-24

Similar Documents

Publication Publication Date Title
US11201498B2 (en) Power supply system
US10543869B2 (en) Electronic control unit and electric power steering apparatus equipped with the same
US9240704B2 (en) Circuit for voltage stabilization in an onboard power supply
US9802562B2 (en) Automotive power unit
US8680717B2 (en) Relay controller
US10862324B2 (en) Power supply system
US10804714B2 (en) Relay device and in-vehicle system
US10048305B2 (en) Semiconductor abnormality detection circuit
JP2008500223A (en) Electronic battery safety switch
US9981684B2 (en) Vehicle power steering control apparatus
JP4934628B2 (en) Dual system power supply
EP3958466B1 (en) Triggering circuit and electronic fuse device incorporating the same
US9537300B2 (en) Load driving device
US11148533B2 (en) Vehicle activation system
EP2998200B1 (en) Electric power steering device
US20170207050A1 (en) Load drive apparatus
US20130076125A1 (en) Load control device
JP2015100158A (en) DC-DC converter
US8283952B2 (en) Circuit arrangement
JP7397987B2 (en) integrated circuit device
JP6084151B2 (en) DC-DC converter
JP7173421B1 (en) Power supply controller
CN111697954B (en) Switching device and method for operating a switching device
KR100858115B1 (en) Electronic battery safety switch
CN112311240A (en) Switching power supply device

Legal Events

Date Code Title Description
FEPP Fee payment procedure

Free format text: ENTITY STATUS SET TO UNDISCOUNTED (ORIGINAL EVENT CODE: BIG.); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

AS Assignment

Owner name: YAZAKI CORPORATION, JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:WATARU, KAZUHISA;REEL/FRAME:053234/0737

Effective date: 20200621

STPP Information on status: patent application and granting procedure in general

Free format text: NON FINAL ACTION MAILED

STPP Information on status: patent application and granting procedure in general

Free format text: RESPONSE TO NON-FINAL OFFICE ACTION ENTERED AND FORWARDED TO EXAMINER

STPP Information on status: patent application and granting procedure in general

Free format text: FINAL REJECTION MAILED

STPP Information on status: patent application and granting procedure in general

Free format text: RESPONSE AFTER FINAL ACTION FORWARDED TO EXAMINER

STPP Information on status: patent application and granting procedure in general

Free format text: DOCKETED NEW CASE - READY FOR EXAMINATION

STPP Information on status: patent application and granting procedure in general

Free format text: NOTICE OF ALLOWANCE MAILED -- APPLICATION RECEIVED IN OFFICE OF PUBLICATIONS

STPP Information on status: patent application and granting procedure in general

Free format text: PUBLICATIONS -- ISSUE FEE PAYMENT RECEIVED

STPP Information on status: patent application and granting procedure in general

Free format text: PUBLICATIONS -- ISSUE FEE PAYMENT VERIFIED

STCF Information on status: patent grant

Free format text: PATENTED CASE

AS Assignment

Owner name: YAZAKI CORPORATION, JAPAN

Free format text: CHANGE OF ADDRESS;ASSIGNOR:YAZAKI CORPORATION;REEL/FRAME:063845/0802

Effective date: 20230331